A Perpendicular Spin Torque Switching based MRAM for the 28 nm Technology Node

Klostermann, Ulrich; Angerbauer, M.; Griming, U.; Kreupl, Franz; Rührig, M.; Dahmani, F.; Kund, M.; Miiller, G.

doi:10.1109/iedm.2007.4418898

Cited by 22 publications

(6 citation statements)

References 8 publications

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“…As compared to the intensively-studied MTJs with in-plane anisotropy, the perpendicular MTJs promises less spintransfer torque (STT) switching current density with higher thermal stability, and tighter switching distribution. [1][2][3][4][5][6][7] The PMA is controlled through the manipulation of the surface/ interface of the materials, which are more robust than the anisotropy defined by the shape of the in-plane MTJs at high memory density. There are several candidate material systems showing PMAs which have been investigated in detail, such as rare earth-transition metal, 8) L1 0 -CoPt/ FePt(001), 9,10) and multilayers.…”

Section: Introductionmentioning

confidence: 99%

Size Dependence Effect in MgO-Based CoFeB Tunnel Junctions with Perpendicular Magnetic Anisotropy

Chenchen

Akhtar

Sbiaa

et al. 2011

Jpn. J. Appl. Phys.

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We examine the effect of junction sizes on the magnetization reversal process and spin-transfer torque switching of the MgO-based CoFeB magnetic tunnel junctions (MTJs) with perpendicular magnetic anisotropy (PMA). From the magnetic field transport measurements, it was found that the miniaturization of MTJs inherently enhances the switching asymmetry and the PMA of the soft layer. Our micromagnetic simulations confirmed that the dipolar field from the hard layer is responsible for the switching asymmetry and the increase in perpendicular shape anisotropy induces improvement of the PMA. It was further revealed that this additional anisotropy gained from the smaller MTJ sizes is not sufficient to sustain the thermal stability to meet the long-term information storage at the state-of-the-art complementary-metal–oxide semiconductor technology node. The pulsed spin-transfer torque measurements showed that a higher current density is needed to switch the magnetization of the soft layer in MTJ with smaller lateral dimensions, which is attributed to the increase in PMA.

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Section: Introductionmentioning

confidence: 99%

Size Dependence Effect in MgO-Based CoFeB Tunnel Junctions with Perpendicular Magnetic Anisotropy

Chenchen

Akhtar

Sbiaa

et al. 2011

Jpn. J. Appl. Phys.

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“…Thus, the longer sensing delay does not cause the read disturbance problem. Since the critical current of the P-MTJ has been reported to be around 30 A [12], the sensing current should be lower than 20 A not to cause the read disturbance with considering variations. Since the worst sensing current of the proposed sensing circuit is 13.31 A that is 44.37% of the critical current of the P-MTJ.…”

Section: Sensing Delay Simulation and Area Estimationmentioning

confidence: 99%

“…Thus, the low sensing current is a critical requirement for the STT-MTJ-based retention flip-flop. It becomes more critical for the perpendicular MTJ (P-MTJ), which has superior scalability but is much more vulnerable to the read disturbance than the STT-MTJ [12]. The retention flip-flop also needs to have fast speed for the high-performance SoC, and it must be robust against the process variation in deep submicrometer technology.…”

Section: Introductionmentioning

confidence: 99%

A Magnetic Tunnel Junction Based Zero Standby Leakage Current Retention Flip-Flop

Ryu

Kim

Jung

et al. 2012

IEEE Trans. VLSI Syst.

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Recently, a magnetic tunnel junction (MTJ), which is a strong candidate as a next-generation memory element, has been used not only as a memory cell but also in spintronics logic because of its excellent properties of nonvolatility, no silicon area occupation, and CMOS process compatibility. One of the representative research areas for the spintronics logic is the zero standby leakage retention flip-flop. Conventional zero standby leakage retention flip-flops have several problems, including difficulty in design optimization among the delay, sensing current, and process variation tolerance, and the insufficient write current. In this paper, a new MTJ based retention flip-flop is presented to solve these problems. The proposed retention flip-flop is designed using industry-compatible 45-nm process technology model. The proposed retention flip-flop achieves a 41.58% reduced delay and a 67.53% lowered sensing current with a 1.06% increased area compared to the previous retention flip-flop. Index Terms-magnetic tunnel junction (MTJ) logic, nonvolatile flip-flop, retention flip-flop, spintronics logic.

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“…A detailed theoretical analysis of STT switching in MTJ with perpendicular anisotropy for 28 nm technology node has been presented at IEDM 2007 [73]. In order to further push the superparamagnetic limit, Spintec already proposed almost 10 years ago [48] to use MTJ stacks having perpendicular-to-plane magnetization and to increase the spin-torque efficiency by integrating in the stack two pinned layers on both side of the storage layer (see Fig.…”

Section: Perpendicular Stt Mrammentioning

confidence: 99%

Hybrid CMOS/Magnetic Memories (MRAMs) and Logic Circuits

Diény

Sousa

Prenat

et al. 2014

Emerging Non-Volatile Memories

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Spintronics (or spin electronics) is a continuously expending area of research and development at the merge between magnetism and electronics. It aims at taking advantage of the quantum characteristic of the electrons, i.e., its spin, to create new functionalities and new devices. Spintronic devices comprise magnetic layers which serve as spin polarizers or analyzers separated by nonmagnetic layers through which the spin-polarized electrons are transmitted. It is considered that spintronics started in 1988 with the discovery of the giant magnetoresistance (GMR) effect, which corresponds to a large variation of the resistance of a magnetic multilayer under the application of a magnetic field [1]. Shortly later, spin valve structures were invented [2]. The latter exhibit GMR at low fields and thereby constitute very sensitive magnetic field sensors. In 1998, they were introduced as sensing elements in readback heads in computer disk drives. More than one billion of such read heads are produced each year. Besides the usual applications of hard disk drives in desktops,

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A Perpendicular Spin Torque Switching based MRAM for the 28 nm Technology Node

Cited by 22 publications

References 8 publications

Size Dependence Effect in MgO-Based CoFeB Tunnel Junctions with Perpendicular Magnetic Anisotropy

Size Dependence Effect in MgO-Based CoFeB Tunnel Junctions with Perpendicular Magnetic Anisotropy

A Magnetic Tunnel Junction Based Zero Standby Leakage Current Retention Flip-Flop

Hybrid CMOS/Magnetic Memories (MRAMs) and Logic Circuits

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